takjas: Try something: move d4-d6-d8, then move your cursor over each square on the board to see if the arrow becomes a hand. It could be a square which doesn't make sense. If it becomes a hand just go there.
Anyway it's probably just a bug in the game, which is too bad because Fencer no longer corrects them. You'd better resign, otherwise this game will just eat away your vacation days.
(Cacher) Si vous attendez que ce soit à vous de jouer, cliquez sur "changer" à côté du "rafraîchissement" sur la page principale, puis réglez le rafraîchissement de la page sur 30 secondes pour que votre tour de jouer apparaisse pplus vite. (Servant) (Montrer toutes les astuces)